Basically, it's a single peak of a triangle wave, centered on some given value $x_i$. Does anyone know if there's a standard name for this sort of function?

For anyone who's interested, the use case is a program that computes the discrete values

$$f_i = \int s_i(x)f(x)\mathrm{d}x$$

for several functions, and then uses them for various numerical computations on the functions $f$. I'm not writing the program (that's been done), just analyzing it, and I'd like to be able to know what keywords to use to look up more information if/when I need it.